Sunday, August 14, 2005

New toxins appear in lakes

Scientists, businesses spar over new substances used in manufacturing as PCB, mercury levels drop.

By Brad Heath / The Detroit News

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A generation after the United States promised to stanch the flow of toxic pollution into the Great Lakes, scientists are finding evidence of a new crop of chemicals building up in the waters.

The risks those toxins pose -- to people or the environment -- still are not fully understood. But scientists and environmentalists say they are concerned because they are being detected in higher levels..

"There are tens of thousands of high-volume production chemicals, and testing every single one of them before they're produced isn't something we're doing," said Matt Simcik, an environmental chemistry professor at the University of Minnesota who has studied emerging chemicals in the Great Lakes.

Among the new toxins researchers have found:

• Flame-retardants known as polybrominated diphenyl ethers, or PBDEs, that were mixed into plastics and other products to keep them from burning. Tests have found increasing levels of the chemicals in the Great Lakes and other parts of the country. Studies show the chemicals have caused thyroid and liver problems in animals, and one type of PBDE has been linked to cancer in rats and mice.

• Chemicals used to prevent stains and keep food from sticking to pans, known as perfluorochemicals. Researchers from the University of Iowa have detected the chemicals in water taken from Lakes Erie and Ontario. Animal studies suggest the chemicals can interfere with the liver and other organ functions.

These increases are coming as levels of chemicals such as PCBs and mercury -- singled out for elimination because of the threat they pose to the water -- continue to drop. Some environmental groups now are asking the U.S. and Canadian governments to add PBDEs and other chemicals to lists of pollutants that threaten the lakes.

It is unclear precisely how the chemicals end up in the water. Scientists suspect some of the contamination comes from consumer products that aren't disposed of properly; some also enters the lakes through sewage systems that aren't built to filter out the chemicals.

One of the biggest makers of PBDEs, Indianapolis-based Great Lakes Chemical Corp., signed an agreement with the U.S. Environmental Protection Agency in December to stop producing two of the three types of PBDEs. The company referred questions to an industry group, which said there's little evidence the chemicals are harmful.

"There's a lot of concern, but there's not a ton of science," said John Kyte, the North American program director for the Bromine Science and Environmental Forum, which represents flame retardant manufacturers.

"What we have with PBDEs is the huge leap from presence to danger, and the assumption that the mere presence, even at extremely low levels, is harmful."

He said forcing companies to prove products aren't toxic before they're produced is virtually impossible because chemicals can impact people and the environment in so many ways that there's no way to test them all.

Part of the problem is that it's difficult to prove something is toxic until it comes into contact with animals or people, said Norbert Kaminski, director of the Center for Integrative Toxicology at Michigan State University.

"There wasn't an intent to make toxins and to put them out into the environment," he said.

In the long term, that creates a cycle of pollution and cleanup, said Rachel Heckl, who coordinates clean production and toxics issues for Great Lakes United, an environmental group based in Buffalo, N.Y.

"It's impractical and totally unsustainable to just release this stuff and then find out it's a problem," she said.